I have not been so successful. Today, I tried System 2.0 / Finder 4.1 with the HD20 INIT (ver. 1.1), and I get no special messages at all in the Welcome to Macintosh dialog (no "Disassembler Installed" nor anything else). My external 800k drive LED doesn't flash once either, which it normally does at the same time the HD20 INIT loads during boot. And when I get to the Finder and insert a disk into my 800k drive, I hear the buzzing motor sound, which is indicative of the HD20 INIT not having been loaded. I then put in a formatted 800k disk, and the Mac asks me to initialize it because it can't understand my 800k disk. And when I initialize, only one second later I get an Initialization Failed error dialog. All those shows the HD20 INIT is not loading for me on a 400k System 2.0 / Finder 4.1 floppy inserted into the internal 400k drive of my Mac 512k (with 64k ROMs).
Yes, yes, I made 5 different disks with System 2.0 / Finder 4.1 / HD20 INIT 1.1, with the Systems and Finders copied from 5 different working sources. This proves I didn't have a bum copy of the System or Finder. I also know for a fact which versions I am using because you can check the Finder version from the Apple menu in the Finder, and I have a little app called System Version that I double-click to tell me which version of the System I am using. Yes, I am indeed using System 2.0 and Finder 4.1. And yet, even though it is version 1.1 and was placed in the same "System Folder" as the System and Finder, the HD20 INIT won't load.
And if you're wondering, no, I didn't have my 800k external floppy drive connected via my HD20 hard disk. I had my 800k floppy drive directly connected to my Mac.
But my tests didn't stop there. I tested System 1.1 and Finder 4.1 on a 400k disk, along with the HD20 INIT. The disk boots to the Finder but the INIT doesn't load -- can't see or initialize 800k disks.
I then tried System 1.1 and Finder 1.1g with the HD20 INIT. The disk boots but the INIT won't load -- can't see or initialize 800k disks.
I then tried System 3.0 and Finder 4.1 with the HD20 INIT. The disk boots and the HD20 INIT loads! But, it doesn't make MFS 800k disks. You see, even though the HD20 INIT loads with System 3.0 and Finder 4.1, and even though it can see my 800k disks when I insert them at the Finder, and even though I can choose Erase Disk and have the disk erase, and even though it shows me "799k free" after I erase the disk, if I then boot into an HFS aware System/Finder, I see the single pixel at the upper left corner of every open window on my 800k disk, which proves my 800k floppy is still HFS. Only MFS disks lack that extra pixel. And keep in mind you won't see the extra pixel when using a non-HFS aware system, like System 3.0 and Finder 4.1.
And so, it is clear there is some missing variable here, because I tried different System/Finder combinations and was not able to make an MFS 800k disk. And like I said, based on what Mac128 wrote about his success with System 2.0, I tried 5 times with 5 different floppies using System 2.0 but without success. But for whatever reason, the HD20 INIT loads for me with System 3.0! Nevertheless, it doesn't create MFS 800k disks.
Thoughts would be appreciated. (And of course, it would certainly be nice if a few other of you Mac 512k owners out there could also kindly test this along side Mac128 and myself. No doubt more than two of us on this planet who read this forum have a Mac 512k with 64k ROMs.)